Another technique I've struggled with in several orchestra pieces are rapid sequential descending slurs - is it a lack of coordination? finger independence? strength? (probably some of each). But turns out the main problem is I have too much finger on the string - when I just use the very tips, the amount of movement required is small, and the rapid movements are much easier. Of course this is something my GT has told me about more than once, but it's hard to change unless there's a reason, so I guess I found one. ??
And then there is Maria Luisa - sometimes the run ups are fluid and they sound fine, and sometimes - well let's say they are less than perfect. Then KG suggested to think of them differently - to think of the first 3 notes as one set, diddle dum, then the next 2 notes, the open string (when you move) and the first note after the shift as a pair. Dee dum. This focuses the attention on the landing note (instead of where you've just been) and synchronizes the hands. At least that's what seems to happen, and bingo! I have had to correct so many things to get those shifts to work consistently I should be grateful. First I wasn't staying in position, or preparing the fingers while I was moving my hand/arm up the fingerboard (so I was falling off the side). When that got fixed the LH/RH coordination problem was revealed. Hopefully that's now all the things that it has to teach me!